1. Field of the Invention
The present invention generally relates to Voice over Internet Protocol (VoIP). In particular, the present invention is related to waking up a VoIP terminal device from a power-saving state.
2. Background Art
Voice over Internet Protocol (VoIP) enables the transfer of voice communications over a packet-switched data network, such as the Internet. Each communication is divided among a plurality of packets (i.e., datagrams) including respective encapsulated portions of the communication. The packets are transferred in a packet stream using Internet Protocol (IP).
Devices that support VoIP communications may be referred to as VoIP terminal devices. A VoIP terminal device may be a dedicated VoIP telephone or personal digital assistant (PDA), for example, which is capable of initiating and receiving telephone calls without the use of a computer. For instance, a dedicated VoIP telephone may be a push-to-talk phone, a one-end phone which is capable of receiving but not making calls, a telephone that is capable of receiving and making calls, etc. In another example, the VoIP device may be a computer having software installed thereon that enables the computer to initiate and/or receive telephone calls. In yet another example, the VoIP terminal device may be a VoIP adapter, which enables communication between a plain old telephone service (POTS) telephone and other VoIP terminal devices in a packet-switched network.
The performance characteristics of VoIP terminal devices differ from those of POTS telephones. For example, a POTS telephone maintains a relatively low power state unless the POTS telephone is ringing. Thus, the operating power (i.e., power consumption) of a POTS telephone is substantially negligible unless the POTS telephone is receiving a call. Conventional VoIP terminal devices, on the other hand, remain in a relatively high (i.e., standard) power state at all times because placing a conventional VoIP terminal device in a relatively low power state (i.e., a power-saving state) substantially compromises its ability to process packets that are used for signaling and user information transfer. For instance, placing a conventional VoIP terminal device in a power-saving state substantially hinders its ability to process packets that are necessary for waking up the VoIP terminal device from the power-saving state.
Thus, systems, methods, and computer program products are needed that enable VoIP terminal devices to wake up from a power-saving state.